C4 - Bacterial Metabolism Flashcards
What term describes the biochemical reactions used by bacteria to break down and synthesize compounds?
Bacterial metabolism
What is analyzed to determine a microorganism’s carbon source utilization?
Substrate utilization
What diagnostic aspect looks at the production of specific substances from substrates?
End product production
Diagnostic schemes to analyse each unkwon microorganism
- Utilization of substrates
- Production of End products
- pH
What term describes the breakdown of chemical substrates coupled with oxidation-reduction reactions?
Energy production
What are the two mechanisms bacteria use to produce energy from carbohydrates?
Fermentation and Respiration
What type of process is fermentation?
Anaerobic
In fermentation, what type of compound is used as the electron acceptor?
Organic compound
What tests are used to identify anaerobic bacteria in fermentation?
Voges-Proskauer (VP) and Methyl Red Tests
What term describes the energy-generating process where molecular oxygen is the final electron acceptor?
Respiration
How efficient is fermentation in energy generation?
Less efficient
What accumulates in the medium as a result of fermentation?
Mixture of end products (lactate, butyrate, ethanol, acetoin)
What type of bacteria use respiration for energy production?
Obligate aerobes and facultative anaerobes
What can certain anaerobes use as final electron acceptors in anaerobic respiration?
Inorganic forms of oxygen (nitrate and sulfate)
What are the three major biochemical pathways bacteria use to break down glucose to pyruvic acid?
Embden-Meyerhof-Parnas (EMP) Glycolytic Pathway,
Pentose Phosphate Pathway,
Entner-Doudoroff Pathway
What is the major pathway for converting glucose to pyruvate?
Embden-Meyerhof-Parnas (EMP) Glycolytic Pathway
What reducing power is generated by the EMP Glycolytic Pathway?
NADH2
What energy molecule is produced by the EMP Glycolytic Pathway?
ATP
Is the EMP Glycolytic Pathway aerobic or anaerobic?
Anaerobic
Which pathway is an alternative to the EMP pathway and produces ribulose-5-phosphate?
Pentose Phosphate (Phosphogluconate) Pathway
What does the Pentose Phosphate Pathway provide for nucleotide synthesis?
Pentoses
What reducing power does the Pentose Phosphate Pathway generate?
NADPH
Which bacteria use the Pentose Phosphate Pathway and are heterolactic fermenting?
Lactobacilli
Which bacteria use the Pentose Phosphate Pathway and lack some enzymes required in the EMP pathway?
Brucella abortus
In the Entner-Doudoroff Pathway, what is converted to pyruvate and glyceraldehyde phosphate?
Glucose-6-phosphate
How many NADPH molecules are generated per molecule of glucose in the Entner-Doudoroff Pathway?
One NADPH
What is the ATP requirement for the Entner-Doudoroff Pathway?
One ATP
Which bacteria use the Entner-Doudoroff Pathway and are aerobic?
Pseudomonas,
Alcaligenes,
Enterococcus faecalis
What type of bacteria also use the Entner-Doudoroff Pathway due to lacking certain glycolytic enzymes?
Other bacteria (lmao yan lang nasa ppt)
What is the major end product of alcoholic fermentation?
Ethanol
Which organisms are known for alcoholic fermentation?
Yeasts
Anaerobic Utilization of Pyruvic Acid (Fermentation) examples
A. Alcoholic Fermentation
B. Homolactic Fermentation
C. Heterolactic Fermentation
D. Propionic Acid Fermentation
E. Mixed Acid Fermentation
F. Butanediol Fermentation
H. Butyric Acid Fermentation
What is the end product of homolactic fermentation?
Lactic acid
Which genera are known for homolactic fermentation?
treptococcus and Lactobacillus
What additional products are produced in heterolactic fermentation besides lactic acid?
Carbon dioxide, alcohols, formic acid, and acetic acid
Which bacteria are examples of heterolactic fermentation?
Some lactobacilli
What is the major end product of propionic acid fermentation?
Propionic acid
Which bacteria are known for propionic acid fermentation?
Propionibacterium acnes and some anaerobic non-spore-forming, gram-positive bacilli
What acids are produced in mixed acid fermentation?
Lactic,
acetic,
succinic, and
formic acids
What test is based on the production of strong acid in mixed acid fermentation?
Methyl red test
Which bacteria are known for mixed acid fermentation?
Escherichia, Salmonella, Shigella
What are the end products of butanediol fermentation?
Acetoin (acetyl methyl carbinol) and 2,3-butanediol
What test detects acetoin in butanediol fermentation?
Voges-Proskauer (VP) test
Which bacteria are known for butanediol fermentation?
Klebsiella, Enterobacter, Serratia
What is the end product of butyric acid fermentation?
Butyric acid, along with acetic acid, CO2, and Hydrogen
Which bacteria are known for butyric acid fermentation?
Clostridium, Fusobacterium, Eubacterium
What is the relationship between the VP reaction and the methyl red test?
Organisms positive for the VP reaction usually have a negative methyl red test, and vice versa.
Energy Utilization
- Biosynthesis of new cell components
- Maintenance of the physical and chemical integrity of the cell
- Activity of the locomotor organelles
- Transport of solutes across membranes
- Heat production
What is the most important pathway for the complete oxidation of a substrate under aerobic conditions?
Krebs or Tricarboxylic Acid (TCA) cycle
In the Krebs cycle, what happens to pyruvate?
Pyruvate is oxidized, creating carbon skeletons for biosynthesis and donating electrons to the electron transport chain.
What are the results of the Krebs cycle?
Production of acid and evolution of carbon dioxide
How is fermentation detected in carbohydrate utilization?
By acid production and a color change due to a pH indicator in the culture medium
What must be absent for accurate testing of the ability to ferment a sugar other than glucose?
Glucose
What enzyme is responsible for transporting lactose across the cell wall into the bacterial cytoplasm?
β-galactoside permease
What enzyme breaks the galactoside bond in lactose fermentation, releasing glucose?
β-galactosidase
Can all organisms that ferment lactose also ferment glucose?
Yes
